Solvent for acetyl cellulose.



UNITE STATES PATENT orFIc WILLIAM G. LINDSAY, or NEW YORK, N. Y.,Assmnort 'ro THE CELLULOID COMPANY,

OF NEW YORK, N. Y A CORPORATION OF NEW JERSEY.

j soLvE 'r FOR ACETYL cELLuLosE.

No Drawing.

the city of New York, State of New York,

have invented certain new and useful Improvements in Solvents for AcetylCellu-.

' lose, of which the following is a specification.

The various compositions to which the present invention relates areemployed in the arts, namely, as imitations of natural substances and infilms used for photographic and therapeutic purposes, and consist ofsoluble acetyl'cellulose combined with or dissolved in'certain othersubstances or menstrua. i

Although the final or useful form of the different compounds of thisclass is that of a solid or dried material, the diflerent processes ofconversion into this final solid form involve, 'as is well'understood,the employment of solutions or mixtures of varying consistency as toplasticity, stifliness or fluid.-

ity dependent generally upon the proportion and kind of solvent used tothe amount of the soluble acetyl cellulosef There aretwo classes ofsolvents; liquids \vhich'are solvents in themselves, 'such asepichlorhydrin, dichlorhydrin, acetone, etc.; and solvents which areformed by combining two or more substances with each other. Thecomponents of the mixed solvent in such a case may not necessarily bepossessed of individual solvent power; for instance,

in the case of nitrocellulose ethyl alcohol, which is practically anon-solvent in itself forms a good solvent mixture when camphor isdissolved in it. Thevarious applications of this art require theemployment of complex mixtures in the solvent-single substances beingrarely used for such purpose. Hence, while the advancement of the arthas depended largely on the discovery and application of new singlesolvents yet it has also required the invention of combinatiors ofsolvents by which effects are produced quite diiferent from thoseproduced when single solvents are employed alone.

The action of some solvents or diluents.

Specification of Letters Patent. Application filed August 25, 1911;

Serial No. 646,066.

is quite distinct from that of others in that they require a shorter orlongertime for- "ents so..that the resultingsolid is homogeneous,without air bubbles, without marks, and is pellucid or even transparentand translucent. M i

It is well knownthat there are some varieties of'acetyl cellulose whichare ,soluble in acetone, but the films produced "by a solution of acetylcellulose in acetone often are Patented. May 28,1912.

not films or solid bodies having all the prop erties desired.

I have discovered that acetyl cellulose films having great flexibility,translucency and of a permanent nature can be produced by adding to asolution of acetyl cellulose in acetone a non-solvent liquid'such asbenzylbenzoate. Benzylbenzoate is a non-solvent of acetyl cellulose byitself and in its applicat-ion is merely compatible with the othersolvents used and does not exercise anyindependent solvent power of itsown, so far as I have been able to discover, although its action, ofcourse, may be modified by admixture with the other solvents. At allevents I have discovered that benzylbenzoate, a non-solvent of acetylcellulose by itself but possessing a low volatility, exerts a beneficialeffect upon a solution of acetyl cellulose in acetone or other single ormixed solvents which have a high volatility.

As one example of carrying out my invention I proceed as follows: Idissolve one part of acetyl vcellulose in ten parts (by weight) ofacetone, to this mixture I add .2

parts of triphenylphosphate, or similar sub-.

stance, and .01 part of urea and from 2 to 5 parts of benzylbenzoate.The film produced by the evaporation of this solution has great'flexibility and does not become brittle and disintegrate in anyappreciable length of time. It will be understood, of course, by thoseskilled in the art that these precise proportions of ingredients are notessential, and therefore I do not limit-myself to these specificproportions. Y

Having thus described my invention, iztetyl cellulose dissolved inacetone to which What I claim is: benzylbenzoate has been added,substan- 10 1. A colmp'ositign of mitter consilsting oi tially asdescribed. acetyl ce lulose issolve in a so vent o 5 relatively highvolatility to which benzyl- WILLIAM LINDSAY benzoate has been added,substantially as .Witnesses: described. MABEL DENTON,

' 2.- A composition of matter consisting of 'J. E. HINDON HYDE.

